Traditionally, detergent compositions have been formulated to a composition pH of greater than about 7. A basic pH helps to ensure that the surfactant systems, enzymes, or other organic solvents remain solubilized in the wash water. Furthermore, a basic pH helps to ensure that greasy or oily stains removed from soiled clothing are dispersed in the wash water.
However, it has been found that certain acidic detergents (i.e., with pH less than about 7) may provide benefits, such as improved removal of residues from fabrics and associated improvement in whiteness, improved bleachable stain removal, and self-preservation benefits. Such acidic detergents have often employed surfactants such as linear alkyl benzene sulfonates (LAS), which remain stable at low pHs. On the other hand, sulfated surfactants, such as alkyl sulfate (AS) and alkyl ethoxylated sulfate (AES), have generally been avoided in low pH detergents because sulfated surfactants are known to be susceptible to hydrolysis, particularly at acidic pHs. The use of sulfated surfactants is desirable, however, because sulfated surfactants may provide benefits, such as cleaning performance and sudsing capabilities. There exists a need, therefore, for sulfated surfactant compositions with improved chemical stability at acidic pHs.
Additionally, consumers continue to desire whiteness benefits from laundry detergents. Bleach is capable of delivering whiteness benefits but presents formulation challenges in liquid compositions. It is known that certain performance polymers, such as polyamine compounds, may be used to provide cleaning and/or whiteness benefits as an alternative to bleach.
It has surprisingly been discovered that certain polyamine compounds, in addition to providing cleaning and/or whitening benefits, are capable of stabilizing sulfated surfactants in low pH detergents.
Furthermore, many consumers launder fabrics by hand. Such consumers may desire detergents that provide mildness to the skin, a desirable feel while washing, and suds that form while washing but are readily rinsed away. It has been found that low pH detergents comprising sulfated surfactants and certain polyamine compounds can address one or more of these needs.